Phylogenetic status, distribution, and biogeography of Cryptocercus (Dictyoptera : Cryptocercidae)

Recent morphological studies on Blattaria, as well as molecular data on both these insects and their fat body bacterial endosymbionts, do not agree with Grandcolas's phylogenetic placement of Cryptocercus deep within the Polyphaginae [Grandcolas. P. 1999. Systematics, Endosymbiosis, and Biogeography of Cryptocercus clevelandi and C. punctulatus (Blattaria: Polyphagidae) from North America: a Phylogenetic Perspective. Ann. Entomol. Soc. Am. 92: 285-291]. Therefore, we retain the traditional classification and proposed geographic time frame for evolution of this taxon, which is supported by recent estimations of molecular evolution on endosymbionts (70-25 MYBP) and by geological evidence indicating a window of opportunity for transcontinental movement in North America for an insect with the ecological requirements of Cryptocercus (65-34 MYBP). Further refinement and integration of these hypotheses with the biogeography of related taxa awaits the development of a single, phylogenetically based, internationally accepted classification of relevant cockroach genera, and an explicit delineation of the relationships among extant species of Cryptocercus

Detritivory, coprophagy, and the evolution of digestive mutualisms in Dietyoptera

We review literature on extant detritivores, including cockroaches and termites, and conclude that coprophagy was the key behavior leading to the evolution of hindgut fermentation systems in the stem group of Dictyoptera. Coprophagy exploits concentrated microbial consortia on cellulose based substrates. These microbes are potential mutualists and food, but they also initiate degradation of cellulose, detoxify allelochemicals and soften the substrate, a phenomenon known as the "external rumen". We suggest that the evolution of a sophisticated hindgut fauna is a process of internalizing this self-assembled microbial community, accompanied by changes in host-microbe interdependence, the source of microbial inoculum for neonates, and host social behavior. Proctodeal trophallaxis evolved from pre-existing intraspecific coprophagous behavior when termite ancestors became subsocial, because the physiology of encystment in oxymonad and hypermastigid flagellates precludes their transfer via cysts in adult feces. The behavior was reinforced by the benefits of using the trophic stages of flagellates as food. The association of these flagellates with the dictyopteran lineage is an ancient one, and may have originated as part of the external rumen in the Carboniferous coal swamps

Description of Cryptocercus clevelandi (Dictyoptera: Cryptocercidae) from the northwestern United States, molecular analysis of bacterial symbionts in its fat body, and notes on biology, distribution, and biogeography

Previously published studies on distribution, gut fauna, glandular secretions, karyotypes, 12S and 16S mitochondrial ribosomal DNA (rDNA) sequence divergence, and reproductive isolation suggest that at least 2 species have been included in the taxon Cryptocercus punctulatus Scudder. Here we present morphological and biological studies of the insects, including 16S rDNA sequence divergence of their bacterial endosymbionts in the fat body. We conclude that the name C. punctulatus should be restricted to populations from the Appalachian region of the eastern United States. Those in southern Washington, Oregon, and northern California in the northwestern United States are a distinct species here assigned to Cryptocercus clevelandi by G. W. Byers. The genus Cryptocercus now consists of 4 species, whose distribution suggests an early Tertiary origin

Tergal glands of male and female Cryptocercus punctulatus scudder (Dictyoptera : Cryptocercidae) : Composition, sexual dimorphism, and geographic variation of secretion

International audienceMales and females of Cryptocercus punctulatus possess tergal glands, but they differ in position, size, morphology, and secretion chemistry. Compound A (linalyl acetate) is the most abundant of the 21 compounds found only in the secretion of these glands. Compound B, 4,6,8-trimethyl-7,9-undecadien-5-ol, is specific to the tergal secretion of females.C. punctulatus lives only in the United States; its distribution is disjunct. Compound A is found in samples from the eastern population but is absent in samples from the western population. The amount of compound B per gland in samples from the western population is at least twice as high as in the samples from the eastern populations